1. Field of the Invention
The present invention relates to a disposable and reusable spacer rack, for placing between a pallet and a stack of thin sheets such as printing paper, and to a method of using the disposable and reusable spacer rack hereof. More particularly, the present invention relates to a substantially rectangular disposable and reusable spacer rack, having a plurality of parallel grooves formed in an upper surface thereof. The spacer rack according to the present invention is provided for use in conjunction with a pallet, in supportively holding a stack of printing paper or other printable sheet stock thereon, for use in a continuously fed, high-volume printing press.
2. Description of the Background Art
Many different types of support pallets and skids, for supporting a load thereon, and which are adapted for movement by a forklift, hand truck, or similar device, are known today. Examples of some types of pallet configurations, and other known types of support apparatus, may be found in U.S. Pat. Nos. 3,853,234, 4,269,556, 4,378,743, 4,871,063, 5,042,397, 5,299,691, 5,463,965, 5,493,962, 5,537,935, 5,601,035, and 5,609,557.
In a continuously fed, high-volume printing operation, using a continuous-feed type of printing press such as, e.g., the Heidelburg Speedmaster model, the conventional approach to loading blank paper into a printing press begins with a step of obtaining a quantity of paper, or other thin sheets of stock material to be printed, which has previously been neatly stacked on top of a conventional wooden pallet. The paper or other printable stock is shipped in this form, from a distributor or manufacturer thereof, to a point of use. Then, after shipment to a print shop where the printing press is located, the paper is manually removed from the shipping pallet, and is manually re-stacked on a specially designed grooved skid, which is provided for supporting a stack of paper as it is fed into the printing press.
The grooved skid used in this process is sold as an accessory to the printing press, and is highly machined to close tolerances. The grooved skid includes a metal base that has machined wheels attached to a bottom surface thereof, for riding in floor rails, and locking clamps for fixing the position of the skid. Since the specialized grooved skid is so complicated and highly machined, it is relatively expensive.
This type of continuous feed printing press also includes a mechanized platform, that is slowly and continuously being raised up during automated operation of the press, to allow individual sheets of paper to be removed from the top of the stack, and fed into the press. When the skid is fully loaded, it is slid on the floor rails and moved on to the platform, which is also provided with built in rails to receive the skid. Then, after other appropriate preparatory steps are taken, the press begins taking paper from the stack, and the platform is moved up automatically as paper is removed therefrom.
When the stack of paper on the moving platform gets relatively short, its weight is less than the weight of a tall stack would be. When the platform reaches a predetermined height on the press, a plurality of support rods or spears are then inserted into, and fed in through, the grooves of the grooved skid, and are then engaged in suitable receptacles, formed in support members which are located at a fixed height on the press, behind the platform. Since the weight of the stack is light at this stage of the process, the spears or support rods alone are able to support the weight thereof. The platform and grooved skid are then both lowered down, away from the support rods and the short stack of paper, and brought to the bottom of travel of the platform, close to the shop floor. The empty grooved skid is then removed from the platform.
A second specialized grooved skid, with a full stack of fresh paper thereon, is then brought to the press and carefully placed on the platform via the rail mechanism, below the short paper stack and support rods. Then, the platform is raised up until the top of the new stack fits snugly against the support rods and touches the bottom of the short stack. The support rods are now located between the old, short stack and the new stack. Finally, the support rods are removed.
The entire process is later repeated, when the platform again gets close to the top of its range of motion. In this way, a continuous supply of paper for the printing press is assured.
While the above-described conventional process for restocking a printing press with fresh paper xe2x80x9con the flyxe2x80x9d is useful, and provides paper to the press in an uninterrupted fashion, it nevertheless has some drawbacks and limitations. In particular, it is inconvenient that a fresh pallet of paper comes from the supplier neatly stacked, but has to be manually unloaded from the pallet, and then manually re-stacked. This is a labor-intensive, and therefore costly step. Further, the specialized grooved skids and the floor rail mechanism therefor are relatively expensive, and represent a significant investment for the printer.
Another known approach to feeding paper into this type of printing press is to place a commercially available press-ready skid, stacked with paper, into the press on the platform, to run the press while the paper supply lasts, and later to shut down the press when the paper supply runs out. The empty skid is removed, and a new press-ready skid full of paper is then installed, while the press is shut down. This approach is quite inefficient and disadvantageous, because of the significant down time associated therewith. It is highly preferable to have the printing press running continuously for extended periods of time, and even run around the clock by shift workers.
A specially manufactured plastic pallet is commercially available which is made for use with the above-described type of printing press, the pallet having a flattened upper surface with grooves formed therein to receive the support rods or spears in the above-described process. Plastic pallets of this type are available from Jeco Plastic Products, Inc. of Plainfield, Ind.
While these commercially available modified pallets are useful, they are still relatively expensive, and if a print shop wishes to receive paper pre-stacked on these pallets, it is necessary to purchase and ship the special pallets to a paper distributor, and to make special arrangements to have the paper installed thereon.
Still further, it has been proposed to modify or retrofit a conventional pallet or skid for use with above-described type of printing press by nailing wooden strips to the top boards of the pallet or skid in a spaced arrangement to define grooves for receiving the support rods or spears in the above-described process. Such modified pallets or skids are disadvantageous for several reasons, including the labor-intensive nature of the modification procedure, the lack of uniformity in the grooves thus formed, and contamination of the paper stock caused by transfer of water, dirt, and other foreign matter from the modified pallet or skid which directly supports the stock.
What is needed is a system and apparatus whereby a conventional shipping pallet could be placed directly on top of the lowered platform, with the paper neatly pre-stacked thereon, and used in a printing press without any labor-intensive unloading and restacking, but which could retain the advantageous features of the existing approach, including a slotted or grooved spacer apparatus, for inserting the support rods into, below a short stack of paper, to allow for paper reloading while the press is in operation.
Preferably, a spacer rack could be designed which would work with existing machines, including the support rods or spears thereof, is free of imperfections and contaminations, is relatively inexpensively so as to be disposable, but is sufficiently durable to be re-usable.
The present invention provides a disposable and reusable spacer rack apparatus for cooperating with a pallet to support a stack of printing paper thereon. A spacer rack apparatus according to a first embodiment of the present invention, generally, includes a substantially rectangular body member, the body member including a substantially flattened base portion having an upper surface and a lower surface, and a plurality of parallel spaced apart divider slats attached to the upper surface of the base portion. The parallel spaced apart divider slats define a plurality of open grooves therebetween, for receiving support rods therein during a paper change process.
In a preferred embodiment of the present invention, the spacer rack apparatus is integrally formed as a single unit, out of relatively inexpensive materials, such as cardboard, recycled plastic, or open-celled plastic foam.
A spacer rack apparatus according to a second preferred embodiment of the present invention is formed from a sandwich-type intermediate body in a machining operation. The intermediate body includes an upper facing which is a first thin sheet of material, a lower facing which is a second thin sheet of material substantially identical to the upper facing and oriented parallel thereto, and a central core, which is disposed between the upper and lower facings and is attached thereto. The central core is formed from a matrix material including wall sections oriented substantially transverse to the upper and lower facings. The central core may be formed in a hexagonal honeycomb pattern, with cells thereof having a diameter of between xc2xd inch and xc2xe inch in diameter.
Accordingly, it is an object of the present invention to minimize the amount of labor required for re-stocking a contiuous feed type of printing press with paper.
It is a further object of the present invention to provide a method and apparatus for restocking a printing press with paper, which would allow re-stocking during operation thereof, but which would obviate the necessity for manually unloading and re-stacking the paper.
It is yet a further object of the present invention to provide a less expensive alternative to the customized grooved skid which is currently used to load paper into the above-described type of printing press.
For a more complete understanding of the present invention, the reader is referred to the following detailed description section, which should be read in conjunction with the accompanying drawings. Throughout the following detailed description and in the drawings, like numbers refer to like parts.